Hairspring for time instruments



July 23g @4 J. R. PUTNAM HAIRSPRING FOR TIME INSTRUMENTS Fild Sept. 19, 1938 2 Sheets-Sheet l MY 23p 394 J. R. PUTNAM 2,2%172 HAIRSPRING FOR TIME -INSTRUMENTS Filed Sept. 19, 1958 2 Sheets-Sheet 2 4l# A? I #8 7 l 5 w z//d/f Patented July 23, 1940 PATEl'i-ifi @FFME HAIRSPRING FOR TIME INSTRUMENTS James R. Putnam, Prospect, Conn., assigner to The Waterbury Clock Company, Waterbury,

Conn., a corporation of Connecticut Application September 19, Iii-i3d, Serial No. 230,558

3 Claims.

- The present invention relates to improvements in spiral hairsprings for measuring-instruments and more especially concerns ya superior spiral hairspring for organization with the movement `5 of a timepiece, such as a watch or a clock.

One of the objects of the present 'invention is to entirely or substantially eliminate a number of interferences affecting the precision of a timeinstrument, whereby a time-piece featured by Iaccuracy of high degree is obtained.

Another object of this invention is to provide improved means for maintaining substantially isochronous motion of a balance-wheel, whereby a time-movement of improved precision is secured.

A lfurther object of this invention is to provide yfor organization with the movement of a timepiece a superior spiral hairspring so formed as to eliminate interferences affecting regulated isochronous motion of a balance-wheel, whereby a time-movement of superior precision characteristics, is obtained.

Still another object of the present invention is to organize with the movement of a timeinstrument, a spiral hairspring of improved construction, w-hereby need for repairs and adjustments is substantially lessenedand inconvenience and expense caused thereby are largely avoided.

A still further object of the invention is to provide a superior spiral hairspring for the purposes described which may be economically fabricated at little or no cost above the cost of spiral hairsprings currently produced.

With the above and other objects in view, as

v will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out the present invention are. shown for illustrative purposes:

Fig. 1 is a broken View in front elevation showing an escapement-mechanism for a timepiece embodying a spiral hairspring formed in accordance with the present invention;

Fig. 2 is a transverse sectional view thereof taken on the line 2-2 of Fig. 1 through the front and back plates;

Fig. 3 is a detached plan view of the spiral hairspring shown in Figs. 1 and 2; and

Fig. 4 is a similar view of a modified form of spiral hairspring.'

'connection with the embodiments of the invention chosen for illustration, an escapementmechanism is employed which may generally be of more or less `conventional character but which is -distinguished by the organization therewith of the spiral ,hairspring-of the present invention, the said spiral hairspring being herein generally designated by the reference character Il.

As is shown particularly well in Fig. 2, the parts about to be described are supported by or between a front-plate i2 and a back-plate i3. Through an opening provided in the said back-plate i 3 the shank ci a bearing-stud ill passes and the endface of .the shank is provided with a conicalrecess which forms a bearing-seat i5. Aligned with and arranged opposite to the said bearingstud lll is a bearing-screw ifi the shank of which is threaded and is threaded through an opening in the front-plate i2. As described in connection with the bearing-stud lil the bearing-screw lr6 is provided in the end-face of its shank with a conical-recess which likewise forms a bearingseat I'l.

Rotatively supported in the bearing-stud i4 and the bearing-screw iii for oscillating movement is a balance-staff i8. As is shown particularly well in Fig. 2 the said balance-stan.c IS at its respective opposite ends is tapered to provide cone-bearings i-i. One of the said 'conebearings i9 is received in the conical bearing-seat i5 of the bearing-stud ifi. The other cone-bearing i9 enters the conical bearing-seat il' in the bearing-screw it which is adjustable in the frontplate I2.

Staked on the balance-stad lil is a collet or hairspring hub 2i, the purpose of which will be described, and a balance-wheel 22. From its hub-portion 23 the balance-wheel 22 is cut-out radially to its outer edge at diametrically opposite portions thereof, providing two spokes 24-24.

Carried by the balance-wheel 22 is the usual impulse-pin 25 for engaging an impulse-lever connected with an escape-wheel, not shown, and 4 a portion of the said balance-steli adjacent the hub-portion 23 of the balance-wheel is cut-out to provide clearance for the said impulse-lever.

Securely held in place against the forward face of the vback-plate i3 by the head of the bearing-stud ill and a friction-washer 26 engaged thereby, is a regulator-lever 2l' for the said hairspring li. The said regulator-lever 2l is preferably formed with a hub-portion 28 having an opening of larger diameter thanv the diameter of the opening in the front-plate i2. Against the front face of the hub-portion 2l around the said opening therein the rear face of the frictionwasher 25 abuts. This friction-washer 25 may be composed of spring-material and its front face about the opening therein is engaged by the head of the said Abearing-stud i4. As will be understood the shank of the bearing-stud ini passes through the opening in the said friction-washer, through the opening in the regulator-lever and through the opening in the said front-plate.

Extending radially from the hub-portion 28 of the regulator-lever in opposite directions respectively are arms 253 and 30. At the distal end of the arm 35i the regulator-lever is quarter-turned the collet or hub 2l.

to provide a loop or tail-piece 3| which extends at substantially a right-angle to and rearwardly from the said. arm 30. As shown the said loop or tail-piece 3l is provided with a slot 32 for receiving the outer convolution 3'I of the spiral hairspring I I, as will be described more fully hereinafter.

Coming now to the description of the improved spiral hairspring of the p-resent invention, the terminal-portion 36 of the innermost spiral or convolution 35, as is shown particularly well in 'ig. 1, is attached in any suitable manner to The outermost convolution 31, as is shown in Figs. 1 and 2, passes through the slot 32 in the loop or tail-piece 3l of the regulator-lever 2l. Adjacent its free end the said outermost convolution 3'1 is. formed to provide a locating-bend 38 whereby an attaching-terminal 39 thereof can be located with respect to an opening 4B in a bracket-member il secured to the back-plate I3. As is shown, see Fig. l, the attaching-terminal 3S is received in the said opening il and is held in place in the bracketmember Il! by means of a keeper or wedge-pin 42.

A feature of the present invention is .the special arrangement of some of the convolutions of the spiral hairspring II with respect to other convolutions of the said hairspring.

As is particularly well shown in Fig. 3, in one embodiment of the invention the spiral hairspring il may be said to be comprised of agroup of interiorly-arranged convolutions substantially uniformly spaced apart one from the other, and a group of outer convolutions which are spaced from each other relatively-widely with respect to the spacing between the convolutions of the said group lying interiorly thereof. In this' illustrative example the outermost convolution 3l' which for convenience will be called the first outermost convolution is more widely spaced from its adjacent convolution here to be referred to as Y. the secondoutermost convolution d3 than the said second outermost convolution 33 is spaced from the next succeeding or third outermost convolution lid. Furthermore the spacing between the said second outermost convolution d3 and the said third outermost convolution fili is wider than the spacing between the convolutions lying interioriy of the said third outermost convolution.

In Fig. 4 there is shown a modified form of spiral hairspring t5 in which substantially the same effect is secured as is obtained with the hairspring of the preceding figures, with respect to the spacing between outer and inner groups of convolutions of the spiral hairspring. In this embodiment of the invention the spacing between the adjacent convolutions of the spiral hairspring llprogressively widens from the innermost convolution 6.16 to the iirst outermost convolution fil. As will be clear, the spacing between the said iirst outermost convolution ill' and the second outermost convolution 48 is relatively-Wider than the spacing between the said second outermost convolution F53 and the third outermostconvolution "I9, which spacing in turn is relatively-larger than the spacing between adjacent coils lying interiorly of the said third outermost coil.

In the operation of an ordinary timepiece clashing occursbetween convolutions of the spiral hairspring. This generally involves the first few outermost convolutions of the hairspring. Overriding of convolutions caused, for example, by shocks or jars also takes place, VWhen such conditions are present the hairspring will not properly perform its function of controlling the motion of the balance-wheel and this will result in non-uniform pulsations or impulses. Clashing of convolutions of the hairspring usually causes a timepiece to run fast.

Spiral hairsprings formed in accordance with the invention herein described eliminate the disturbing defect in timepiece operation caused by the clashing or overriding of convolutions of the hairsprihgs. By forming the few outermost convolutions more widely spaced from each other than are the remaining convolutions, these coils do not come into contact and the desired isochronous motion of the balance-wheel is maintained. In this manner not only is the Yprecision of the timepiece improved but the Yneed of fre'- quent adjustments and repairs and inconveniencev and expense caused thereby are also materially diminished.

The invention may be carried out in other speciiic ways than those herein set forth` without'departing from the spirit and essentiall characteristics of the invention, and the present 'embodiments are, therefore, to be considered inall respects as illustrative and not restrictive, and all changes coming within themeaning and equiva-` lency range of the appended claims are intended' to be embraced therein.

I claim: g i

l. As a new article of manufacture, a-spiral hairspring for time-instruments comprising two groups of spiral convolutions, one of the said groups being an inner group having theconvolutions thereof substantially uniformly spaced apart, and the other of the said groups being arranged exteriorly of the inner group and having its rst, second and third. outermost convolutions morel widely spaced from each other than the spacing between adjacent convolutions of the said-inner `groups. of spiral convolutions, one of the said groups beingan inner group having the convolutions thereof substantially uniformly spaced apart, and the other of the said groupsI being arranged exteriorly of the inner group and'having its rst, second and third outermost convolutions more widely spaced-from each other than the spacing between adjacent convolutions of the said inner group, and the spacing between the said nrst and second outermost" convolution's'being wider than the spacing between thev said second and third outermost convolutions. l

3. In a time-movement the combination of: a spiral hairspring and a rotatably-mounted regulator therefor, having spring-engaging means; the said spiral hairspring comprising two groups of spiral convolutions, one of the said groupsbe-- volution having a portion thereof engageable byv the saidspring-engaging means arranged concentric to the path of rotation of the said regulator.

JAMEs R. PUTNAM. f 

